1. Field of the Invention
The invention relates to a projection technique, and more particularly, to an indicating unit, an indicating apparatus, and an indicating method for deducing a touch position in a projection system.
2. Description of Related Art
Recently, the related projection applications became more and more popular depending on development of projection technique.
In a conventional projection system, an infrared indicator is used to actuate an infrared light emitting diode to emit an infrared light when the infrared indicator contacts with a screen. Then, an infrared receiving module receives the infrared light and deduces a touch position on a projection surface. However, when a user holds the indicator, the infrared light is blocked by a hand of the user at some angles, which causes the infrared receiving module located behind the user being unable to receive the infrared light. For example, the indicator is used to draw lines and the lines are not continued. Therefore, regarding the use of indicators, users have to pay attention to the holding angle at all times. Consequently, the current techniques for the use of indicators are rather inconvenient for users.
U.S. Pat. No. 6,717,073, U.S. Pat. No. 7,703,926, and U.S. Patent Publication No. 20110169778 all disclose that an indicator is applied in a projection system. However, the indicators provided by the foregoing prior art still remain great inconvenient for use.